It is known that fuel injectors are provided with fuel return lines through which the fuel which is not consumed at the fuel injector is returned to the tank. The fuel injector provides a drain passage for this purpose to which a connector for a retaining clamp can be attached. The retaining clamp for its part possesses a connecting fitting for the fuel return line. In this way, the excess fuel can be drawn off to the tank.
The retaining clamp is designed as a self-locking clip and has two retaining arms which partially encircle the fuel injector. Since the retaining clamp must not become detached from the fuel injector or loosen its seat during operation, it is seated relatively tightly on the fuel injector, which has the disadvantage that relatively high installation force is necessary to push the retaining clip onto the fuel injector.
Furthermore, devices for generating negative pressure by utilizing the venturi principle are sufficiently known. A flowing medium is accelerated by means of a restriction in the cross section, which reduces the pressure of the medium. The suction line opens into this area of reduced pressure so that a fluid can be sucked in through this suction line.
Fuel injectors possess a return line through which excess fuel is transported back to the tank. A slight negative pressure obtains in this return line so that the fuel is, so to speak, suctioned off by the fuel injector. This has the considerable advantage that the fuel injector does not have to build up positive pressure to remove the excessive fuel and that the return line does not have to be designed for pressure. A device which utilizes the venturi system is used to generate the negative pressure in the return line. The high-pressure line in which the pressurized fluid is flowing is connected, for example, to the fuel pump and is supplied with fuel under pressure. This fuel is accelerated in the device and thereby generates the necessary negative pressure for the return line to suction off the excess fuel from the fuel injector.
It would be desirable to provide a device of the type mentioned above with which, firstly, the installation force to push the device onto a fuel injector is reduced, secondly, the retaining force, or the pull-off force, is increased, or at least not reduced. It would be advantageous if the device consists of only a few parts and is simple to assemble and install.